DESCRIPTION: Preliminary evidence suggests that individuals who show excessive cardiovascular responses to psychological challenge (exaggerated "cardiovascular reactivity") may be at increased risk for the development of atherosclerosis and coronary heart disease (CHD). To the extent that exaggerated reactivity exerts a causal, cumulative influence on disease processes, this effect should be observed primarily among those who are exposed to frequent, ongoing stressors which trigger exaggerated cardiovascular responding. A prospective test of this diathesis-stress theory would require a) a valid method of assessing the daily stressors which evoke cardiovascular activation and b) a strategy for reliably documenting the progression of underlying disease processes (i.e., atherosclerosis) in community samples. "Social support," the availability of assistance from others, is a second behavioral factor which has been linked with CHD, with individuals lacking in social support showing a poorer prognosis in a number of studies. As with cardiovascular reactivity, the influence of social support on atherosclerosis may be best characterized in humans by tracking individuals in their daily life circumstances, and following the progression of disease over time. These approaches have not been feasible until now. The proposed study examines the joint influence of cardiovascular reactivity and ongoing psychological stress as they influence the development of carotid atherosclerosis in a sample of middle aged adults; the effects of social support processes on response to psychological stressors and disease progression will be simultaneously explored. The sample will be followed over a three-year period using: a) reliable laboratory measures of cardiovascular reactivity; b) real time ambulatory monitoring assessments of behavioral stressors, social interactions and cardiovascular responses; and c) repeat assessments of subclinical atherosclerosis using carotid ultrasonography. These recent measurement innovations, as employed in the present study, should significantly enhance our current understanding of the role of behavioral processes in coronary heart disease risk.